Any discussion of the background art throughout the specification should in no way be considered as an admission that such art is widely known or forms part of common general knowledge in the field.
In teleconferencing, the measurement and management of the user call quality experience (sometimes loosely referred to as the Quality of Service—QoS) is an important part of assembled and or integrated voice and video conferencing systems.
The QoS is used as a measure of the user experience and likelihood of complaint about the service quality. Since the provision of higher quality network links is normally directly related to the cost of operation, QoS measures are routinely used to balance the allocation of resources to match the required QoS against the premium price structures and requirements for customer retention. Since customer complaints as expensive, and customer churn (migration of customers between service providers) is important to minimize, the balance of these two factors is critical to the operating efficiency and profit of any voice or video conferencing operator. In summary, the two factors that are balanced using a measure (objective, subjective or complaint based) of the user experience based on QoS, service provision cost due to bandwidth, server processing loads, server location or managed proximity and network link quality. Increasing any or all of these adds cost to the service provider.
Perceived fault conditions attributed to the operator increase the level of customer complaints, lower the user experience and ultimately can lead to customer loss.
There are many known systems for the measurement of QoS. In particular, a prevalence in techniques to estimate the individual link and aggregate QoS. The most common measure of individual link quality is a Mean Opinion Score (MOS) defined in (ITU 1996). Known systems are often associated with the estimation of a measure related to the MOS against the voice, background noise, interaction and overall conference experience. The following prior art is cited as exemplary disclosures in this space:
United States Patent Publication US 2009/0257361 proposes the use of a shadow server to monitor link quality and associate with call link quality;
(ETSI_TC-TM 1996) Discloses an E-model that has a low computational complexity means of estimation of the call channel quality;
(Ramachandran and Beeram 2009) United States Patent Publications US20090237240 and US20090201824 provide a method for assembling a set of physical parameters that contribute to call issues;
United States Patent Publication US2009/0225670 provides a means of aggregating individual Link QoS measures to provide an overall conference QoS.
IT (ITU-T G.114 2003) provides a prediction of MOS degradation related to network link latency.
U.S. Pat. Nos. 7,403,487 and 6,343,313 also provide for example systems for the measurement of QoS levels in networked conferencing environments.
Most of the known systems, on first inspection, appear to focus on the time delay (i.e. latency) between users in the communications channel, and also the connection and disconnection times (i.e. of the device connection itself) in the estimation of the QoS. As such, the reference to metrics and quality of service relate to the standard metrics of the audio quality, interaction latency and therefore the likely degree of over talk, and other simple metrics such as packet loss. These can be referred to as ‘physical metrics’ as they represent some fairly simple and measurable aspect of the physical (or associated software and network) system and its performance. The level of degradation of call quality is inferred, using models such as (ETSI_TC-TM 1996) from the physical observable parameters.
‘In Service Monitoring’ (ISM) is often a key feature in prior art Voice systems. ISM is used for monitoring the system and becoming aware of degradation of quality before losing customers. In some cases it can be used to achieve lowest cost by maintaining the lowest acceptable quality to users. However, detectable issues with audio and system performance are not always linked to user complaint. Sometime the fault mode is known to, and accepted by the user (for example using a phone in a noise public space giving poor audio quality). In other cases, the form of the distortion may be perceptually insignificant despite some conventional objective measure noting it is high.